The water is now more than 6 feet below the record high, set in October 1986. The water level is tracked by gauges placed around Lakes Michigan and Huron, which are actually one body of water connected by the Straits of Mackinac. Daily measurements are then averaged at the end of each month for record-keeping purposes.

The lakes have recently been setting individual monthly records, but Tuesday's announcement means the lakes are now lower than they have ever been for any month since modern record-keeping began in 1918.

Hydrologists had been expecting the lakes to dip to a level never seen before, given the relatively warm and dry weather over the past year.

“Not only have water levels on Michigan-Huron broken records the past two months, but they have been very near record lows for the last several months before then,” said John Allis, chief of the Army Corps' Great Lakes hydraulics and hydrology office.

“Lake Michigan-Huron's water levels have also been below average for the past 14 years, which is the longest period of sustained below-average levels since 1918.”

Water levels on the Great Lakes fluctuate seasonally by inches and by as much as several feet over a period of years, depending on long-term weather patterns. But they were previously bracketed by the record low of March 1964 and the record high of October 1986.

Now the lakes are headed into uncharted territory, and some want the U.S. and Canadian governments to do something about it.

While nature is the big driver for water levels, humans also have played a role by dredging the St. Clair River, which is the main outflow for the lakes. Deepening the river's channel to open the door for oceangoing freighters has increased the amount of water that can flow out of Michigan and Huron, into Lake Erie, over Niagara Falls and, eventually, out to the Atlantic Ocean.

Federal officials have long acknowledged that dredging and riverbed mining in the St. Clair dropped the long-term average of the lakes by about 16 inches. But a Great Lakes water-level study recently completed by the U.S. and Canadian governments revealed that unexpected erosion since the last major St. Clair dredging project in the early 1960s dropped the lakes' long-term average by an additional 3 to 5 inches.

That means the lakes today are nearly 2 feet lower than they would be if humans hadn't meddled with the St. Clair's riverbed.

Conservation groups, some property owners and a group representing the region's mayors want the U.S. and Canadian governments to begin exploring some type of remediation project in the St. Clair River to slow the flows and gradually restore the lakes to more closely match their historical averages.

Not everyone supports the idea. They worry such a structure could exacerbate erosion problems if high water ever returns.

On Tuesday, Sierra Club of Canada issued a news release urging the governments to act, noting that a riverbed restoration had been planned before the 1960s dredging project, though it was never built.

“At these numbers, it would take years of consistent rain to naturally improve the situation,” Roger Gauthier, a retired Army Corps hydrologist, said in the Sierra Club of Canada release. “Water levels can be restored responsibly by gradually installing sills at the head of the St. Clair River. . . . It's time for governments to work to finish the job, before we have further disasters.”

Members of the International Joint Commission, a binational body that oversees U.S.- Canadian boundary water issues, are now digesting the thousands of public comments they received after the release of the study on Great Lakes water levels.

John Nevin, spokesman for the Joint Commission, said Tuesday that the members have not made a decision about whether to recommend to the U.S. and Canadian governments some type of restoration project for the St. Clair River.

“The key point is, the commission has not taken a position with respect to the St. Clair River and remediation,” Nevin said.

Nevin said the Joint Commission should issue a recommendation within the next few weeks on what - if anything - should be done in the St. Clair .